Hi Arul,
As you rightly said, its a problem of rights. It looks like while migrating reports from Dev to Prod the security groups are not transfered properly.
Do following steps for set of reports and one group of users:
- Assign security rights (as per your requirement) to one set of reports for one user group
- Assign security rights (at least view on demand) for same user group on universe as well (it shoulod cover all the universes which are used
- Now test the reports
- If successful, replicate the same for all the reports and user groups.
Let us know your feedback.